The first mass trial of an HIV vaccine which has yielded promising
results in smaller tests in the United States and elsewhere is
to be launched in AIDS-hit South Africa, it was announced.

The South African AIDS Vaccine Initiative said the programme,
baptised Phambili or "Going Forward" in the Xhosa language,
will be conducted jointly with the HIV Vaccine Trials Network
of the US National Institutes of Health.

"Three thousand participants will be recruited from four
South African provinces -- Gauteng, North West, Western Cape and
KwaZulu-Natal," it said in a statement.

The trial sites include the township of Soweto outside Johannesburg,
Cape Town and Durban.

The "test of concept" vaccine, developed by US firm
Merck, has been tried on more than 1,800 people across the United
States, Canada, Latin America, the Caribbean and Australia.

The vaccine contains three HIV genes but not live HIV and therefore
cannot infect volunteers.

Lawrence Corey, lead researcher for the HVTN conducting the study
said: "This trial will answer several major scientific issues
that face all of us in the field of HIV-vaccine development.

"It will determine the usefulness of vaccines that induce
high immune response to the parts of the virus that are similar
between different strains of HIV."

South Africa has one of the world's highest rates of HIV infections,
with more than 5.5 million infected people out of the national
population of 47 million.

In the more-than 25-year history of AIDS, only one prototype
vaccine, AIDSVAX, has completed the vast process of human trials
and it proved to be a disappointing failure.